DCP 7020. Scan either flat bed or sheet feeder weak print. Light documents very weak print. What are indications when drum needs replacement? I have cleaned glass, and sheet feeder bar. Also set contrast to max. No change.

Either sensitive drum of the tonner is damaged or the high temperature fuser roller damaged. Check and replace.

Most likely all you need is to clean the rubber feed rollers. Use alcohol.

Black hair lines can come from what is called the slit glass. Does the line appear when you can from just on the glass? If that scan is OK and the line appears when you run through the document feeder than the small glass just before the top glass needs a good clean, or sometimes in the machine the optics has some dirt on it.

Check the print document to see if the ink rub of easily,if so this mean the fuser cartridge need to be change.Turn off the printer and wait until it is cool before changing the fuser cartridge because the fuser get very hot when ever the printer is in use.









Open the fuser cartridge door. On most printers this door will be either on the left-hand side of the printer or in the back. Consult your owner's manual for the exact location. Flip down the clips that hold the cartridge in place, then grasp the handle and pull it out of the printer.
Push the new fuser cartridge in until it snaps into place, then flip the clips up to lock it in place. Close the fuser cover door.
Open the toner cartridge door and remove the toner cartridge. On most laser printers the toner cartridge is located either in the front of the printer or on the right-hand side.
Vacuum underneath the toner cartridge to remove all paper dust and toner residue. This debris has a tendency to build up and cause streaks and stains on the paper.
Wipe the interior of the printer with a soft cloth to remove any remaining debris that could cause problems with print quality. Continue cleaning the printer until all debris is removed.
Purchase a set of laser printer cleaning sheets, and load one or two in the paper tray. Print to those sheets of paper to clean the paper path. These sheets are slightly sticky, and they are designed to remove dirt and debris from the paper path.
You should also clean the print drum and the corona wires.

Remove the drum and toner from the front cover of the machine. On the top right of the drum unit there is a tab that you can slide. Please slide it 20 times from left to right and bring it back to home position.

Dear sir you see properly drum unite has a drum image sensor its demage so you change your copier drum unite, thanks.

There is probably a little switch that gets tripped when the document feeder is in correctly. This is preventing you from scanning from the glass.

Open the document feeder and clean the scanner glass

Try updating the driver you didn't say if you are using  VISTA or not?

http://www.brother-usa.com/Downloads/Default.aspx

Does the line show up on PRINTS FROM YOUR COMPUTER also, or only when SCANNING A DOCUMENT? If the line is only from scanned documents, the SCAN GLASS has something stuck on it. The SCAN GLASS is a GLASS **** located under the ORIGINAL FEEDER. It is NOT the plate of glass you place the original on . Look UNDER the original feeder for a scrap of paper stuck in the optical path of the GLASS ****, and remove the scrap, or CLEAN THE SCAN GLASS IF CORRECTION FLUID, INK, ETC ARE STUCK ON IT. If the line shows up on ALL prints, your CHARGE CLEANING SLIDER located in the IMAGING (DRUM) UNIT must be slid all the way to one end of the charger, OR IT WILL CAUSE A BLACK LINE ON ALL PRINTS. Otherwise, the IMAGING UNIT may need to be cleaned or replaced. Toner smudges on the drum would indicate need for cleaning or replacement.